An Engagement with Sherlock Holmes
by kitcat234
Summary: Joan Watson just can't seem to catch a break - whether it's fighting with chip and pin machines or racing across London on the word of her sociopath flatmate, she's always right in the middle of the chaos. When Sherlock and her go undercover as a couple to catch a serial killer, things get...interesting. Fem!John. This is a WIP - I'm going to revise and rewrite.


**Author's Note:** This actually was in my dream and I woke up and knew I had to write it. Please let me know what you think, because it's my first time writing for this fandom. And sorry it's not Johnlock exactly. It had to be fem!John to work for the story. Moffat and Gatiss are wonderful, brilliant assholes who own this wonderful story and I am simply their fan, wanting to kill them for only leaving us with "rat, wedding, bow."

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"Drycleaning for Sherlock Holmes?"

"That's it," Joan replied.

It was just another day for Joan Watson. Here she was, doing the mundane chores for her flatmate while he, the marvelous and mysterious Sherlock Holmes, pissed off and ran about without telling her what was going on. She did hate when he did that. She wasn't just around to pick stuff up for him, and she would like it if once he had to fight with the chip and pin machine instead of her. She was just paying when a blur of dark colors rushed into the shop.

"Joan, I've found her," Sherlock said, his words almost running together in his hurry.

"What?" Joan always felt a little dull when Sherlock caught her off-guard like this and she had to be caught up. Sherlock shot her a disapproving look and huffed impatiently.

"Come on."

"Now?"

"No, in a leisurely ten minutes, _of course now_, Joan!"

And with that, he took off, forcing Joan to shout a, "I'm sorry. I'll get them tomorrow," to the confused clerk before she ran after Sherlock. They ran through London, weaving through streets, hopping over low walls and trashcans as they took shortcuts through alleyways, running for what must have added up to about three miles. Sherlock stopped suddenly at the mouth of an alleyway opposite a club called Coquette. They leaned against the wall, catching their breath, Joan coughing slightly as Sherlock's keen eyes scanned the club's entrance.

"Why do we never seem to take a cab anymore?" asked Joan as she finally started to breathe normally.

"No time," said Sherlock. "Our killer is in there right now."

"Our killer," Joan said in slight disbelief, "is in a club and you had me run here? What the hell, Sherlock?"

Sherlock, of course, was not paying her words the slightest attention. He was straightening his shirt, which was bordering on too tight, not that Joan noticed it or wished to unbutton that shirt at all, and pulling something out of his pocket.

"Put this on," he said as he handed her something.

Joan looked down and realized she was holding an engagement ring. A very nice engagement ring. It was a solitaire and the diamond looked about 1.5 carats. If this was real, this cost at least £15,000. Stunned she was even holding something that expensive after Sherlock had just tossed it at her, she looked up and saw he had just slipped a wedding band onto his left ring finger.

"What is going on, Sherlock?"

"Put the ring on, Joan."

"Sherlock," she said in a reprimanding tone that she knew would make little difference to her insufferable flatmate, who just sighed in an irritated fashion before turning his bright silver eyes on her and speaking quickly and quietly.

"The murders have all been of couples in various states of undress. They are always killed in the middle of having sexual intercourse, but never just with each other. There is always a kiss left on the bodies, but neither is wearing the matching red lipstick. The knife wounds indicated a smaller blade, indicating something that could be concealed easily. It's obvious it's a female killer, blonde, with strong upper body strength. The killer is, of course then, a swinger, and this club caters to couples specifically."

"A swinger. Naturally," Joan muttered sarcastically. She slipped the ring onto her finger, desperately pushing away the fantasy that, somehow, in some kind of parallel universe, Sherlock was giving this to her for a completely different and all the more romantic reason. She noticed Sherlock step closer, but didn't really think much of it – Sherlock really had no sense of personal space – when she felt a tugging at her hair. Sherlock had pulled her hair out from its neat bun and his long, graceful fingers were now carding through it, ruffling it. "Umm, Sherlock…" she asked hesitantly.

"You can't go into a club with your hair in a military bun. Think, Joan," he said, his baritone voice repeating the reproving phrase that she had seemed to get on a daily basis since they had met eight months ago. "Yes, I think that's fine," he mumbled under his breath as he ran his hands through her hair one last time. Joan chided herself silently as a part of her immediately mourned the loss of Sherlock's fingers in her hair, just another part of the fantasy that she had been trying so hard to repress since that day she had seen Sherlock about to take that pill and she had leveled her gun, losing all thought of legality and the words _You don't even know this man!_ that had screamed at her when she had showed up at 221B Bakers Street just a few days before.

"Yes, alright," Sherlock muttered, more to himself than anything, and he took Joan's left hand in his right, weaving their fingers together and beginning to stride across the street, Joan having to quicken her steps to keep up. The fact that his hand felt so warm and reassuring in hers was _not_ making it any easier for her to convince herself she should not fancy Sherlock Holmes.

They walked up to the guard at the door and Sherlock smiled one of his handsome, I-pass-off-perfectly-as-a-completely-sane-man smiles he was so good at (it had honestly scared Joan the first time she had seen it, as it was so completely _not_ the Sherlock smile she knew) and raised their interlocked hands, flashing Joan's ring. The guard nodded and they walked in. Sherlock ducked his head and whispered in her ear, Joan shivering slightly as his hot breath washed over her neck and made the tendrils of hair that fell around her face dance.

"You know what to look for. We'll split up. If you find her first, text me." They started to separate, but he caught her hand again and pulled her back. "And Joan," he whispered, "act natural."

She turned, about to make a sarcastic retort about the irony of Sherlock, the resident sociopath, telling her to act normal, but he was gone, disappeared into the crowd. She made a noise of frustration under her breath and began to look around. There were bodies pressed against each other everywhere and through the hum of talk and the louder thumping of music, she could barely think. She tried to look around, but found it was a bit of a wasted effort – she needed Sherlock's height to be able to see just past the people in front of her. Mumbling something about apparently needing to be tall to be a swinger, she weaved her way through the crowd until she found an entrance to an outdoor patio.

"Oh thank God," she said quietly to herself as she stepped out into the cool air.

"I know; it's like a furnace in there," said a smooth voice next to her.

Joan turned and saw a woman watching her, an expectant smile playing on her pouty and bright red lips. The woman was a few inches taller than Joan, thanks to some dangerously high heels, and she was wearing a tight dress that showed off her ample, and probably fake, breasts, her blonde hair swinging perfectly around her shoulders. Joan immediately checked the woman's arms – muscular and toned, the three-quarter sleeves of the dress clinging to her. Joan's mind immediately went into military mode – what to do when faced with the enemy – but then she caught herself before she could lock up and get defensive. 'Act normal,' Sherlock had said, 'act normal.'

"It's just awful, isn't it? It's too hot to think in there," she said with a pleasant smile.

The woman smiled, inviting yet somehow predatory, like a spider luring a fly into its web.

"Maybe that's exactly what they want – you to not think," she says slowly.

"That would fit, wouldn't it?" said Joan with a laugh. "I'm Joan, by the way."

"Cassandra," the woman said, her voice almost a hiss.

_Beep beep._

"Will you excuse me for one second? That's probably my…husband," she said, trying to sound self-assured, but the thought of being married to Sherlock trips her up. "I lost him in the crowd."

"Not used to saying the word," the woman observed. "Newlyweds?"

"Actually, yes. Quite new," said Joan, trying not to laugh at how 'new,' a quarter of an hour ago, in fact.

No luck in here.

Anything?

SH

Joan looked up quickly, smiling at Cassandra, who was watching her with hooded eyes as she sipped her drink. Cassandra smiled back, a slow calculated smile, and Joan understood how she lured these couples in. The woman was damned attractive. But she was a killer, and Joan had forced herself into the woman's trap.

She's here.

With me.

Outside patio.

JW

She hit send and pocketed the phone as Cassandra watched her carefully, her tongue flicking out and running along her lips, reminding Joan forcefully of a hungry animal, slowly stalking its prey. They continued to talk, Cassandra leading her over to one of the edges of the patio as a small swarm of people stepped out from the surging sea of bodies into the cool air, relief showing plainly on their faces.

Cassandra had just started to move a little closer to Joan when a shadow fell over Joan. She turned her head to see Sherlock standing there, yet another one of his eerily-out-of-character yet devastatingly handsome smiles on his face, his silver eyes darker than usual. He nodded politely to Cassandra as Joan spoke up cheerily.

"Dear, this is-"

Her words were cut off as Sherlock suddenly moved forward. His graceful hands rested on either side of her face as his lips crashed onto hers. She gasped slightly and Sherlock seemed to take all the rest of her air away, kissing her hungrily as his hands moved, one cradling the back of Joan's head as the other slid down her spine to rest low on her back, pulling her hips flush against his. Joan's hands slid up to his face to tangle in his messy dark curls, just like she had in her dreams almost every night since they had met. She stood on her tiptoes and pulled his head down, arching up into the kiss as his arms tightened around her, almost lifting her from the ground. She never wanted to let go, never wanted to have to break this perfect kiss, but Sherlock broke the kiss as abruptly as he had started it.

He turned his head and smiled as Cassandra, who had been watching them the entire time, an almost victorious smile playing on her lips as she admired her new victims. Just then, Lestrade and Donovan walked up behind her, Donovan immediately grabbing Cassandra by the wrist.

"What the-" Cassandra began to say, whirling around to confront the unknown grabber, only to face Lestrade, who held his badge up to her face.

"You're under arrest for the murders of Jacqueline and Thomas Moore, Alecia and Mark Fellows, Mary and Guy Parsons, and Elizabeth and Curt Markaway," he said in his gravelly voice, his brown eyes hard as he surveyed the serial killer. Donovan led the woman out, reading her her rights as they went, and Lestrade looked over at the two of them. "Nice work, you two," Lestrade said. "You-, Joan, are you alright?"

"What?" Joan asked quickly.

"You're all flushed and breathing heavy," said Lestrade, giving her a worried look.

Joan glanced over at Sherlock, who was back to his usual smug self, standing with his hands joined behind his back, a smirk playing on his lips. Of course the bastard had no reaction to that kiss.

"Asthma," she said quickly.

"I didn't know you had asthma," said Lestrade.

"Think I might be developing it," she said quickly. "I'm fine. Really." She gave Lestrade a swift smile.

"Well, thank you, Sherlock," said Lestrade.

"On the contrary," interrupted Sherlock, a pleased note in his voice that was always there just after he'd come up with a brilliant idea or solved a case. "It was all Joan. I just merely phoned you."

Lestrade looked surprised but pleased, and smiled at Joan, clapping her on the back.

"Much thanks, Doctor Watson."

She smiled, finally having regained her normal breathing pattern. Sherlock suddenly turned on his heel, his coat whipping out behind him, and headed out of the club. Joan smiled at Lestrade before hurrying after him. He didn't say anything, but simply walked briskly down the street.

"What was that all about?" asked Joan finally.

"What?"

"That kiss!"

"We were in a couples club. We had to act like everyone else to throw off suspicion. I also needed to distract her so D.I. Lestrade could arrive without her noticing," said Sherlock in his usual manner-of-fact way.

"Ah," said Joan, feeling her heart sink the slightest amount. Of course. "For the case, then." Suddenly, Sherlock stopped and pulled on her hand, spinning her towards him. "Wha-"

Her words were again cut off as Sherlock's lips met hers, swallowing any words she might have wanted to say. His arms wrapped tightly around her waist and, after the millisecond of shock had passed, her arms automatically wrapped around his neck. His head dipped more as he deepened the kiss, Joan kissing back with just as much passion. All too soon, Sherlock broke the kiss and loosened his hold on her waist, backing up enough so he could look at her. His eyes, darker than usual but just as sharp, scanned her face as she tried to catch her breath, her chest heaving. He nodded, seemingly having finished his analysis and let her waist go, continuing his brisk walk down the street. Joan stood there for a moment, completely bewildered before running after him, catching up with him a couple doors down.

"W-what was that for?" she cried, not sure whether to be confused, insulted, angry, or turned on.

Without slowing down, he looked over at Joan, one of his familiar smiled playing on his lips, the one that pulled up the left side of his mouth, making his face look even more angular than it already did. It was the smile Joan saw whenever she said or did something that amused him.

"Personal research," he said, his eyes twinkling at her merrily.

He never did ask for that engagement ring back…


End file.
